The role of fiber gauge length in FWI of data from coiled DAS fibers

Matthew Eaid, Scott Keating, Kristopher A. H. Innanen

Distributed acoustic sensing is an important technology that offers distinct benefits for reservoir monitoring. The increased access they provide to borehole acquisition geometries, has the potential to supply transmission data crucial to successful applications of full waveform inversion on land data. The properties of the fiber such as its geometric shape, and the its gauge length, especially in relation to the geometry, are expected to have implications for parameter resolution in FWI. In this paper we explore the role of the fiber gauge length in FWI, by examining (1) how it affects a given fibers sensitivity to each component of the strain field, and (2) how the relative sensitivity to these strain components affects parameter resolution. This explored through numerical simulations on a simple model on both clean and noisy data, as well as a more complex, and geologically reasonable model.